[RFC PATCH] hwmon: Add driver for Infineon DPS310
Guenter Roeck
linux at roeck-us.net
Thu Apr 27 01:13:05 AEST 2017
Hi Joel,
On Thu, Apr 27, 2017 at 12:03:21AM +0930, Joel Stanley wrote:
> Hi Guenter,
>
> Below is a work in progress hwmon driver for the DPS310[1]. The device does
> both pressure and temperature monitoring over either I2C or SPI. There's a
> public datasheet available on Infineon's website.
>
> I require a driver that reads the temperature data over I2C and exposes it to
> userspace as a hwmon device. I wanted your opinion weather this should be an
> IIO driver (and we could then use the IIO HWMON bridge in our application), or
> if it should be a native HWMON driver?
>
IIO, I think. Pressure isn't really for hardware monitoring, and we would have
a hard time supporting it. IIO already has the necessary infrastructure for it.
Jonathan, any thoughts/comments ?
Thanks,
Guenter
> Once we've agreed on a subsystem I will clean the driver up and submit it
> properly.
>
> Cheers,
>
> Joel
>
> [1] https://www.infineon.com/cms/en/product/sensor/capacitive-pressure-sensor-for-consumer-applications/channel.html
>
> ---
>
> The DPS310 is a temperature and pressure sensor. It can be accessed over
> i2c and SPI.
>
> This driver supports continual measurement of temperature over i2c only.
>
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
> drivers/hwmon/Kconfig | 12 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/dps310.c | 331 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 344 insertions(+)
> create mode 100644 drivers/hwmon/dps310.c
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 190d270b20a2..8229b2f8c591 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1349,6 +1349,18 @@ config SENSORS_DME1737
> This driver can also be built as a module. If so, the module
> will be called dme1737.
>
> +config SENSORS_DPS310
> + tristate "Infineon DPS310"
> + depends on I2C
> + select HWMON_VID
> + select REGMAP_I2C
> + help
> + If you say yes here you get support for the hardware monitoring
> + features of the Infineon DPS310 digital barometric pressure sensor.
> +
> + This driver can also be built as a module. If so, the module
> + will be called dps310.
> +
> config SENSORS_EMC1403
> tristate "SMSC EMC1403/23 thermal sensor"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index d2cb7e804a0f..3a5ad06d6d89 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -52,6 +52,7 @@ obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
> obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
> obj-$(CONFIG_SENSORS_DELL_SMM) += dell-smm-hwmon.o
> obj-$(CONFIG_SENSORS_DME1737) += dme1737.o
> +obj-$(CONFIG_SENSORS_DPS310) += dps310.o
> obj-$(CONFIG_SENSORS_DS620) += ds620.o
> obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
> obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o
> diff --git a/drivers/hwmon/dps310.c b/drivers/hwmon/dps310.c
> new file mode 100644
> index 000000000000..b014f01d0d3f
> --- /dev/null
> +++ b/drivers/hwmon/dps310.c
> @@ -0,0 +1,331 @@
> +/*
> + * Copyright 2017 IBM Corporation
> + *
> + * Joel Stanley <joel at jms.id.au>
> + *
> + * The DPS310 is a barometric pressure and temperature sensor.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/hwmon.h>
> +#include <linux/module.h>
> +
> +#define PRS_B2 0x00
> +#define PRS_B1 0x01
> +#define PRS_B0 0x02
> +#define TMP_B2 0x03
> +#define TMP_B1 0x04
> +#define TMP_B0 0x05
> +#define PRS_CFG 0x06
> +#define TMP_CFG 0x07
> +#define TMP_RATE_BITS GENMASK(6, 4)
> +#define TMP_EXT BIT(7)
> +#define MEAS_CFG 0x08
> +#define MEAS_CTRL_BITS GENMASK(2, 0)
> +#define PRESSURE_EN BIT(0)
> +#define TEMP_EN BIT(1)
> +#define BACKGROUND BIT(2)
> +#define PRS_RDY BIT(4)
> +#define TMP_RDY BIT(5)
> +#define SENSOR_RDY BIT(6)
> +#define COEF_RDY BIT(7)
> +#define RESET 0x0c
> +#define RESET_MAGIC (BIT(0) | BIT(3))
> +#define COEF_BASE 0x10
> +
> +#define TMP_BASE TMP_B2
> +#define PRS_BASE PRS_B2
> +
> +#define TMP_RATE(_n) ilog2(_n)
> +#define TMP_PRC(_n) ilog2(_n)
> +
> +const int scale_factor[] = {
> + 524288,
> + 1572864,
> + 3670016,
> + 7864320,
> + 253952,
> + 516096,
> + 1040384,
> + 2088960,
> +};
> +
> +struct dps310_data {
> + struct regmap *regmap;
> + int interval;
> + s32 c0, c1;
> +};
> +
> +static s32 dps310_twos_compliment(u32 raw, size_t num_bits)
> +{
> + s32 out = raw;
> +
> + if (raw & BIT(num_bits - 1))
> + out = raw - BIT(num_bits);
> +
> + return out;
> +}
> +
> +static int dps310_get_temp_coef(struct dps310_data *data)
> +{
> + struct regmap *regmap = data->regmap;
> + uint8_t coef[3] = {0};
> + int ready, r;
> + u32 c0, c1;
> +
> + r = regmap_read(regmap, MEAS_CFG, &ready);
> + if (r < 0)
> + return r;
> +
> + if (!(ready & COEF_RDY))
> + return -EAGAIN;
> +
> + /*
> + * Read temperature calibration coefficients c0 and c1 from the
> + * COEF register. The numbers are 12-bit 2's compliment numbers
> + */
> + r = regmap_bulk_read(regmap, COEF_BASE, coef, 3);
> + if (r < 0)
> + return r;
> +
> + c0 = (coef[0] << 4) | (coef[1] >> 4);
> + data->c0 = dps310_twos_compliment(c0, 12);
> +
> + c1 = ((coef[1] & GENMASK(3, 0)) << 8) | coef[2];
> + data->c1 = dps310_twos_compliment(c1, 12);
> +
> + return 0;
> +}
> +
> +static int dps310_get_scale_factor(struct device *dev)
> +{
> + struct dps310_data *data = dev_get_drvdata(dev);
> + int val, r;
> +
> + r = regmap_read(data->regmap, TMP_CFG, &val);
> + if (r < 0)
> + return r;
> +
> + /* Scale factor is bottom 4 bits of the register */
> + val = val & GENMASK(3, 0);
> + if (val < 0 || val > ARRAY_SIZE(scale_factor))
> + return -EINVAL;
> +
> + return scale_factor[val];
> +}
> +
> +static int dps310_read_temp(struct device *dev, u32 attr, int channel,
> + long *temp)
> +{
> + struct dps310_data *data = dev_get_drvdata(dev);
> + struct regmap *regmap = data->regmap;
> + uint8_t val[3] = {0};
> + int r, ready;
> + int kT, T_raw;
> +
> + switch (attr) {
> + case hwmon_temp_input:
> + r = regmap_read(regmap, MEAS_CFG, &ready);
> + if (r < 0)
> + return r;
> + if (!(ready & TMP_RDY)) {
> + dev_err(dev, "tmp not ready\n");
> + return -EAGAIN;
> + }
> +
> + /* Choose scaling factor kT based on chosen precision rate */
> + kT = dps310_get_scale_factor(dev);
> +
> + r = regmap_bulk_read(regmap, TMP_BASE, val, 3);
> + if (r < 0)
> + return r;
> + T_raw = (val[0] << 16) | (val[1] << 8) | val[2];
> + T_raw = dps310_twos_compliment(T_raw, 24);
> +
> + /* (c0 * 0.5 + c1 * T_raw / kT) * 1000 m°C */
> + *temp = ((data->c0 >> 1) + (data->c1 * T_raw) / kT) * 1000;
> +
> + return 0;
> + default:
> + return -EOPNOTSUPP;
> + }
> +}
> +
> +static int dps310_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + switch (type) {
> + case hwmon_temp:
> + return dps310_read_temp(dev, attr, channel, val);
> + default:
> + return -EOPNOTSUPP;
> + }
> +}
> +
> +static int dps310_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + switch (type) {
> + case hwmon_temp:
> + /* Fall through */
> + default:
> + return -EOPNOTSUPP;
> + }
> +}
> +
> +static umode_t dps310_is_visible(const void *data,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + switch (type) {
> + case hwmon_temp:
> + switch (attr) {
> + case hwmon_temp_input:
> + return 0444;
> + default:
> + return 0;
> + }
> + default:
> + return 0;
> + }
> +}
> +
> +
> +static const u32 dps310_temp_config[] = {
> + HWMON_T_INPUT,
> + 0
> +};
> +
> +static const struct hwmon_channel_info dps310_temp = {
> + .type = hwmon_temp,
> + .config = dps310_temp_config,
> +};
> +
> +static const struct hwmon_channel_info *dps310_info[] = {
> + &dps310_temp,
> + NULL
> +};
> +
> +static const struct hwmon_ops dps310_hwmon_ops = {
> + .is_visible = dps310_is_visible,
> + .read = dps310_read,
> + .write = dps310_write,
> +};
> +
> +static const struct hwmon_chip_info dps310_chip_info = {
> + .ops = &dps310_hwmon_ops,
> + .info = dps310_info,
> +};
> +
> +static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case PRS_CFG:
> + case TMP_CFG:
> + case MEAS_CFG:
> + case RESET:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case PRS_B2:
> + case PRS_B1:
> + case PRS_B0:
> + case TMP_B2:
> + case TMP_B1:
> + case TMP_B0:
> + case MEAS_CFG:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static const struct regmap_config dps310_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .writeable_reg = dps310_is_writeable_reg,
> + .volatile_reg = dps310_is_volatile_reg,
> + .cache_type = REGCACHE_RBTREE,
> + .use_single_rw = true,
> +};
> +
> +static int dps310_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct dps310_data *data;
> + struct device *hwmon_dev;
> + int r;
> +
> + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->regmap = devm_regmap_init_i2c(client, &dps310_regmap_config);
> + if (IS_ERR(data->regmap))
> + return PTR_ERR(data->regmap);
> +
> + r = regmap_write(data->regmap, TMP_CFG, TMP_EXT | TMP_PRC(128));
> + if (r < 0)
> + return r;
> +
> + /* Turn on background temperature measurement */
> + r = regmap_update_bits(data->regmap, MEAS_CFG, MEAS_CTRL_BITS,
> + TEMP_EN);
> + if (r < 0)
> + return r;
> +
> + /* Get calibration coefficients required for reporting temperature */
> + r = dps310_get_temp_coef(data);
> + if (r == -EAGAIN)
> + return -EPROBE_DEFER;
> + if (r < 0)
> + return r;
> +
> + hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
> + client->name, data, &dps310_chip_info, NULL);
> +
> + if (IS_ERR(hwmon_dev))
> + return PTR_ERR(hwmon_dev);
> +
> + dev_info(&client->dev, "%s: sensor '%s'\n", dev_name(hwmon_dev),
> + client->name);
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id dps310_id[] = {
> + { "dps310", 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, dps310_id);
> +
> +static const unsigned short normal_i2c[] = {
> + 0x77, 0x76, I2C_CLIENT_END
> +};
> +
> +static struct i2c_driver dps310_driver = {
> + .class = I2C_CLASS_HWMON,
> + .driver = {
> + .name = "dps310",
> + },
> + .probe = dps310_probe,
> + .address_list = normal_i2c,
> + .id_table = dps310_id,
> +};
> +module_i2c_driver(dps310_driver);
> +
> +MODULE_AUTHOR("Joel Stanley <joel at jms.id.au>");
> +MODULE_DESCRIPTION("Infineon DPS310 driver");
> +MODULE_LICENSE("GPL");
> --
> 2.11.0
>
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